Originally Posted by
Jipe
The same problem exists for 20" wheels.
To have about the same biggest gear inch as a Rohloff with a 54x13 with 35x349 wheels, with 35x406 wheels and a cassette with a 11t smallest cog, a 60t chainring is required.
Moulton that uses 20" wheels with 28x406 tires, mount a special cassette with a 10t smallest cog and a 58t biggest chainring.
Riese & Müller mount a 9-32t cassette with a 52t chainring on its derailleur Birdy Touring with 40x355 or 50x355 wheels (50x355 has an overall diameter very close to the one of 28x406, its the reason why its possible to mount ETRTO406 wheels on a Birdy).
My apologies I'm a little confused. I thought your main concern was surrounding the arm and its weight on the derailer. I understand the roll-off does happen objective advantage in range. I also noticed that discrepancy with a cog sizes. What interests me in this case is an affordable alternative most seem to not have considered trying. At the very least it would be an interesting attempt right?